JP3140320U - Screw conveyor cooling structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure for a screw conveyor which is applied to an incinerator or a melting facility and used for discharging dust in a corrosive gas so that low temperature corrosion due to contact with the corrosive gas does not occur. Cooling.
In a screw conveyor 50 including a screw shaft 2 and a screw blade 3 provided on the outer periphery of the screw shaft 2, the screw shaft 2 has a double tube structure including an inner tube 4 and an outer tube 5. In addition, a water channel 6 through which the cooling water W is circulated is formed in the inner tube 4, and an air layer 7 is formed between the inner tube 4 and the outer tube 5 of the screw shaft 2. An air layer 7 is formed over the circumference.
[Selection] Figure 1

Description

  The present invention relates to a screw conveyor that is applied to, for example, an incinerator, a melting facility, or the like and discharges dust in a corrosive gas, and more particularly, to an improvement in its cooling structure.

In general, as a dust discharge device installed in incinerators, melting facilities, etc., a screw conveyor equipped with a cooling structure that combines thermal protection from high temperature corrosive gas and dust and cooling of dust is adopted. Yes.
Thus, as a cooling structure of this type of screw conveyor, a cooling structure using a cooling medium such as air or water is known as disclosed in Patent Documents 1 to 10, for example.

Japanese Utility Model Publication No. 7-21447 Japanese Patent Laid-Open No. 7-27320 Japanese Patent No. 2613736 JP-A-7-27321 JP-A-8-166116 JP-A-9-250730 JP 2001-310813 A Japanese Patent Laid-Open No. 2002-210738 JP 2007-168911 A JP 2000-327126 A

However, when air is used as the cooling medium, the cooling effect of the screw shaft is not sufficient, and there is a risk that it will be worn out in a short period of time.
On the other hand, when water is used as the cooling medium, the surface temperature of the screw shaft can be lowered sufficiently, but conversely, there is a possibility that low-temperature corrosion accompanying contact with the corrosive gas proceeds.
By the way, although the thing of patent document 10 has the cooling water channel formed in the center of a screw axis | shaft, and the gas flow path divided | segmented into plurality around it is formed, these are comprised just like a lotus root hole. Therefore, a portion where the surface temperature of the screw shaft directly decreases due to the cooling water partially occurs, and therefore, there is a possibility that the low temperature corrosion accompanying the contact with the corrosive gas may proceed.
In short, none of the conventional ones can be cooled so as not to cause low-temperature corrosion due to contact with corrosive gas, and the appearance of such a thing has been desired.

  The present invention was devised in view of the problems described above, and the problem is that a screw conveyor that can be cooled so that low-temperature corrosion due to contact with corrosive gas does not occur. In providing a cooling structure.

  The cooling structure of the screw conveyor according to the present invention basically includes a screw shaft provided with a screw shaft and screw blades provided on the outer periphery of the screw shaft. The screw shaft includes an inner tube and an outer tube. The double pipe structure is characterized in that a water channel for circulating cooling water is formed in the inner pipe, and an air layer is formed between the inner pipe and the outer pipe of the screw shaft.

  Since the cooling water flows through the water channel, the screw shaft is cooled by the cooling water. At this time, since an air layer is formed outside the water channel, the screw shaft is cooled so that the surface temperature of the screw shaft does not fall within the low temperature corrosion temperature range (120 to 130 ° C.). Since the air layer is formed over the entire outer periphery of the water channel, the surface of the screw shaft is uniformly cooled over the entire periphery.

  It is preferable that the middle part of the water channel has an enlarged diameter with respect to both ends. If it does in this way, the flow rate of cooling water can be made slow in the intermediate part of a water channel, and a good cooling effect can be acquired.

  The air layer is preferably configured such that the air circulates between the air layer and the outside. In this way, the temperature of the air layer can be kept constant, and the cooling effect can be made uniform.

According to the present invention, the following excellent effects can be achieved.
(1) Since an air layer is formed over the entire circumference of the water channel, it can be cooled by using water and air together, and this can be used to reduce the surface temperature of the steel material in a high temperature / corrosive atmosphere environment. It is possible to lower the temperature within a range that does not fall within the low temperature corrosion temperature range (120 to 130 ° C.).
(2) According to the above (1), it is possible to prevent a decrease in strength and a low temperature corrosion when the steel is heated to a high temperature.
(3) By setting the working temperature of the steel material to a more appropriate temperature range, it becomes possible to select a cheaper material.
(4) The cooling water can be diverted from the facilities in the facility, and even if cooling air is required, it can be diverted from the facilities in the facility or can be handled by highly versatile equipment. Therefore, the equipment cost and running cost required for cooling are not excessive.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a cooling structure of a screw conveyor according to the present invention. 2 is a cross-sectional view taken along line 2-2 of FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 4 is a cross-sectional view taken along line 4-4 of FIG.

  The cooling structure 1 is composed of a screw shaft 2, a screw blade 3, an inner tube 4, an outer tube 5, a water channel 6, and an air layer 7, and is applied to a screw conveyor 50.

  The screw conveyor 50 is applied to an incinerator, a melting facility, or the like, and in this example, is used as a dust discharge device installed in a waste heat boiler.

  Thus, the screw conveyor 50 includes a casing 51 formed in the lower portion of the waste heat boiler, a dust inlet 52 for receiving the dust that has fallen and formed in the entire upper portion of the casing 51, and a lower portion of the casing 51. A dust outlet (not shown) that is formed on one side for discharging dust, a screw shaft 2 that is provided through both ends of the casing 51, and both ends of the screw shaft 2 that are provided outside the casing 51. , A bearing means 53 that rotatably supports the sealing member 54, a sealing means 54 that is provided between the casing 51 and the screw shaft 2, and a rotation that is provided outside the casing 51 and rotates the screw shaft 2. Driving means (only a chain sprocket provided on one side of the screw shaft 2 is shown in FIG. 1) 55 and dust provided on the outer periphery of the screw shaft 2 to remove dust And a spiral screw blade 3 for conveying the. An appropriate refractory material 56 is lined inside the casing 51.

The screw shaft 2 is made of a metal such as steel and has a double tube structure including an inner tube 4 and an outer tube 5. Further, the inner tube 4 has an appropriate gap between the inner tube 4 and the outer tube 5. An appropriate number of support plates 8 are fixed to the inner tube 4 in order to maintain.
Thus, a water channel 6 is formed inside the inner tube 4, and an air layer (that is, an air chamber) 7 is formed between the inner tube 4 and the outer tube 5.

The water channel 6 is configured such that the cooling water W circulates, and a water supply source such as a pump is provided at the water inlet 9 and the water outlet 10 via rotary joints 11 and 12 provided on both sides of the screw shaft 2. (Not shown) is connected.
Thus, the middle portion of the water channel 6 is expanded with respect to both end portions. That is, this is done by making both end portions of the inner tube 4 have a small diameter, a middle portion having a large diameter, and a taper between them.

  In this example, the air layer 7 is configured such that air A circulates between the outside and an air supply source (not shown) such as a compressor via a rotary joint 14 at the air inlet 13. In addition to being connected, the air outlet 15 is opened to the atmosphere, that is, to the outside of the casing 51. The screw shaft 2 in the vicinity of the air outlet 15 is provided with a partition plate 16 for guiding the discharged air A in the direction perpendicular to the axis.

  The rotary joint 11 on the side of the water inlet 9 and the rotary joint 14 on the side of the air inlet 13 are integrated so as to be of a double inner pipe rotation type capable of handling water W and air A, and on the water outlet 10 side. The rotary joint 12 is a single type that can handle water W.

  The screw blade 3 is provided on the outer periphery of the screw shaft 2 and has a spiral shape for conveying dust to the dust outlet side.

Next, the operation will be described based on such a configuration.
When the screw shaft 2 is rotated in a predetermined direction by the rotation driving means 55, the dust from the dust inlet 52 of the casing 51 is conveyed to the dust outlet side by the screw blade 3 and is discharged therefrom.
The cooling water W from the water supply source is circulated as follows: rotary joint 11 → water inlet 9 → water channel 6 → water outlet 10 → rotary joint 12 → water supply source. The air A from the air supply source is discharged into the rotary joint 14 → the air inlet 13 → the air layer (air chamber) 7 → the air outlet 15 → the atmosphere.

Since the cooling water W from the water supply source flows through the water channel 6, the screw shaft 2 is cooled by the cooling water W. At this time, since the air layer 7 is formed outside the water channel 6, the surface temperature of the screw shaft 2 is cooled so as not to fall in the low temperature corrosion temperature range (120 to 130 ° C.).
Since the air layer 7 is formed over the entire outer periphery of the water channel 6, the surface of the screw shaft 2 is uniformly cooled over the entire periphery.

Since the middle part of the water channel 6 has an enlarged diameter relative to both ends, an appropriate cooling effect can be obtained by reducing the flow rate of the cooling water and reducing the thickness of the air layer 7 in the middle part of the water channel 6. Can do.
Since air A circulates between the air layer 7 and the outside, the temperature of the air layer 7 can be kept constant, and the cooling effect can be made uniform.

In the previous example, the middle portion of the water channel 6 has an enlarged diameter with respect to both end portions. However, the present invention is not limited thereto, and for example, the entire portion may have the same diameter.
In the previous example, the air layer 7 is connected to the air supply source and forcibly circulates the air A to and from the outside. However, the air layer 7 is not limited to this. For example, the air layer 7 is omitted from the air supply source. It may be naturally circulated or stored (enclosed) without circulating air A.

The longitudinal cross-sectional view which shows the cooling structure of the screw conveyor of this invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a sectional view taken along line 4-4 of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cooling structure, 2 ... Screw shaft, 3 ... Screw blade, 4 ... Inner pipe, 5 ... Outer pipe, 6 ... Water channel, 7 ... Air layer, 8 ... Branch plate, 9 ... Water inlet, 10 ... Water outlet, 11 , 12 ... Rotary joint, 13 ... Air inlet, 14 ... Rotary joint, 15 ... Air outlet, 16 ... Partition plate, 50 ... Screw conveyor, 51 ... Casing, 52 ... Dust inlet, 53 ... Bearing, 54 ... Sealing means, 55 ... rotation drive means, 56 ... refractory material, W ... cooling water, A ... air.

Claims (3)

  In a screw conveyor provided with a screw shaft and screw blades provided on the outer periphery of the screw shaft, the screw shaft has a double tube structure including an inner tube and an outer tube, and cooling water is supplied to the inner tube. A screw conveyor cooling structure characterized by forming a water channel to be circulated and forming an air layer between an inner tube and an outer tube of a screw shaft.   The screw conveyor cooling structure according to claim 1, wherein an intermediate portion of the water channel has an enlarged diameter with respect to both end portions. 2. The cooling structure for a screw conveyor according to claim 1, wherein the air layer circulates between the air and the outside.

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